Manual for a PLC

Verbatim from a PLC manual I am studying at work, concerning replacing the memory backup lithium battery:

4.5.2 Notice in using

(1) Do not heat the battery or solder the polarity. ( It may cause the reduction of life.)

(2) Do not measure the voltage or short with tester. (It may cause the fire.)

(3) Do not disassemble the battery.

Personally, I have never considered soldering the polarity...but I've measured voltages plenty of times without causing the fire...